Chaser holder



A rii'29 1924., 1,492,426

c. G. CASHMAN CHASER HOLDER Filed Feb. 21, 1920 (Fafence @ad%mc 14 Patented Apr. 29, 1924.v

' UNITED STATES- PATENT OFFKZE.

CLARENCE G. CASHMAN, OI WAYNESBOBO, PENNSYLVANIA, ASSIGNON, BY DIRECT AND MESNE ASSIGNMENTS, TO LANDIS MACHINE COMPANY. OF WAYNE-33030, PENNSYLVANIA, A CORPORATION OF PENNSYIN'ANIA.

CHASE-B HOLDER.

Application filed February 21, 1820. Serial Ho. 860,465.

To all whom it may concern:

Be it known that I, CLARENCE G. Casu- MAN, a citizen of the United States, residing at Waynesboro, in the county of Franklin and State of Pennsylvania, have invented certain new and useful Improvements in Chaser Holders, of which the following is a specification.

My invention relates to improvements in tool holders of the type'which are mounted in rotary cutter heads and ada ted to hold a cutting element or chaser to cm grooves or threads on bolts and the like articles, and particularly to attachments for varying the lead angle or angle between the cutting elements and the work operated upon to cut threads of a difi'erent pitch.

In the common types of cutter heads in use at the present time, the holders supporting the cutting elements or chasers are either of a complicated structure or are not readily adaptable for changing the angles of the chasers, so that it is possible to cut threads of varying pitches. If threads of a certain pitch are being cut and it is desired to change, it is usually necessary to detach and remove the entire set of chaser holders and replace the same with other holders of the proper kind. Also the chasers must be detached from the removed holders and attached to the others. This necessarily is a laborious time-consuming operation and requires the procurement of a multiplicity of sets of chaser holders for cutting right hand threads and also a like number for cutting left handthreads. Obviously, this is a very expensive practice.

It is the object of my invention to provide means for varyin the lead angle of the chasers without c anging the chaser holders, and further to provide lead angle controlling means adapted for application to blocks or holders of the old type by a sli ht modification thereof.

n carrying out my invention 1 provide broadly, one set of chaser blocks for cutting right hand threads and one set for cutting left hand threads, and support the chasers on wedge shaped plates which are more or less inclined or tapered. and removable, and the inclination of which determines the lead angle of the chasers.

In the accompanying drawings forming a part of this specification:

Fig. 1, is a perspective view of a conventional chaser block or holder slotted to receive the lead angle fill plates,

Figs. 2, and 3, are perspective views of the lead angle fill plates showing the slight taper 0 each, which taper varies as the lead angle required,

Fig. 4, is an end elevation of a chaser block with the lead angle fill plates in positlon, and the chaser and lock bar mounted thereon,

Fig. 5, is an end elevation of a conventional chaser block as it is now used, with a chaser and lock bar in position, and

Fi are is a fragmentary view of a modified coating or positioning means for the fill plates.

Referring to said drawings, in which the same reference characters are used to denote corresponding parts in the several views, the chaser holder 1, is of a conventional type and 1s adapted to be pivotally connected to a trunnion, in a conventional type of cutter head, by means of a screw or bolt passing through the opening 2. In order to more clearly point out the novel features of the invention, I have shown in Figure 5, the old or conventional form of chaser holder, in which the chaser or cutter 3, is formed with parallel serrations or cutting teeth 3, extending the length of the body on one face thereof, with its lower edge bevelled to conform to the contour of the cooperating surface or dovetail 4, and its upper edge provided with a shoulder or dovetail 5, to cooperate with one edge of the conventional form of lock bar or clamp 6, the other end of which is adapted to seat on a channel 7 for securing the parts in assembled relation.

When the lock bar 6 is fastened to the chaser block or holder by the screws 8, it is evident that the chaser is held against lateral movement, and the longitudinal movement thereof is controlled by a screw working in the screw way 9, working or hearing against the end of the chaser. This permits adjustment of the chaser toward the work.

It will also be obvious that the amount of edgewise movement or lead given to the chaser is controlled by the inclination of the chaser dovetail or angle and the lock bar channel, and further that no means is provided for changing this lead without substituting another entire chaser block, with a suitable inclination of the chaser and lock bar channels to give the desired lead. This of course necessitates a change of the entire set of blocks.

I overcome this disadvanta e in the following manner: The chaser c iannel 4, and lock bar channel 7, are milled out into the channels 10 and 11, respectively, which are referably rectangular in cross sect-ion.

ins 12 are fastened in the block and extend into the channels.

The channels or slots are adapted to receive the lead angle fill plates 13 and 14, the lower sides of which fit the channels and the upper faces of which are shaped to present a structure similar to the inclined chaser channel 4, and lock bar channel 7, as is clearly shown in Fig. 4:.

Both fill plates have recesses 15, to receive pins 12, for the proper locating of the plates with respect to the chaser holder or block, and fill plate 13, fitting the rectangular channel 10, has a slot 16, to facilitate the passage of the screw in the screw way 9. I have shown the slot 16' in the fill late 13 as having screw threads however In practice the threads might or would be preferabl omitted.

As wi be noted in Figs. 2 and 3, the fill plates are tapered and the amount of taper determines the lead angle given to the chaser.

My invention renders it possible to use one set of blocks for right hand threads, with several sets of fill plates which are inserted as required, and a similar set for left hand threads. Obviously it will be much more economical to change the readily removable fill plates than the entire set of chaser holders, in effecting a change in the lead angle of the chasers.

In Fig. 6, I have shown a modified locating or positioning means for the fill plates 13', which makes the use of the pins 12 shown in Figs. 2 and 3, unnecessary, and permits of further adjustment of the chasers with respect to the chaser holder whenever it is advantageous to do so, as for example, when one chaser does not track the threads traversed by the remaining chasers. To accomplish this I provide adjusting screws 17 and 18 oppositely threaded into screw threaded apertures in said chaser holder 1. An arcuate groove 19 is provided n each end of the fill plates to receive the filister heads of the screws 17 and 18.

I claim:

1. In a cutter head, a chaser holder, a chaser therefor extending lengthwise thereof, and a fill plate interposed between the chaser holder and chaser and extending in the direction of the length of said chaser adapted to determine the angle between the chaser and the axis of the work for cutting threads of a different pitch, substantially as set forth.

2. In a cutter head, a chaser holder having slots, lead angle fill glateshaving lockin surfaces and remova 1y mounted in sai slots, a chaser mounted on one of said lead angle fill lates, a locking shoulder on said chaser and a lock bar connecting the shoulder of the chaser and the other lead angle fill plate, and means for fastening the lock bar to said holder.

3. In a cutter head, the combination with a chaser holder, lead angle fill plates mounted on said chaser holder, a chaser mounted on said lead angle fill plates, and means carried by said chaser holder and engaging said fill plates for longitudinal adjustment there- 0 4. In combination, a chaser holder, a chaser associated therewith, means to deter mine the lead angle of the chaser inter sed between one side of the chaser and the older, a locking bar on the holder engaging the chaser, and means to secure the bar to the holder with its length parallel to the length of the chaser.

5. In combination, a chaser holder, a chaser associated therewith, means to determine the lead angle of the chaser inter osed between one side of the chaser and the older, and means to secure the chaser to the holder.

6. As an article of manufacture, a fill plate for adjusting the lead angle of chasers, said plate having two opposite flat surfaces slightly inclined to each other and having athreaded groove at a longitudinal corner.

7. As an article of manufacture, a fill plate for adjusting the lead angle of chasers, said plate having two opposite flat surfaces slig tly inclined to each other in two directions and having a threaded groove at a longitudinal corner.

'8. As an article of manufacture, a fill plate for adjusting the lead angle of chasers, said plate having two opposite flat surfaces slightly inclined to each other and one longiv tudinal corner being beveled.

9. In a cutter head, a chaser holder, a longitudinally grooved tangential chaser therefor extending lengthwise thereof, and

the chaser and holder, and means for securing the chaser to the holder, substantially as set forth.

11. In a cutter head, the combination with neaeaa a chaser holder, lead an le fill plates mounted on said chaser hol er, a longitudinally grooved tangential chaser mounted on one of said fill plates, and means carried by said chaser holder and engaging said last named fill plates for longitudinal adjustment of the chaser, substantially as set forth.

12. In a cutter head, a chaser holder, a longitudinally grooved tangential chaser therefor, fill plates interposed between the chaser holder and chaser for determining the lead angle of the chaser, and means for fastening said fill plates against endwise movement, substantially as set forth.

13. In a cutter head, a chaser holder, a 15 longitudinally grooved tangential chaser therefor extending lengthwise thereof, fill plates interposed between the chaser holder and chaser and extending in-the direction of the length of said chaser adapted to de- 20 termine the angle between the chaser and the axis of the work for cutting threads of a difi'erent pitch, and -means for fastening said fill plates against movement, substantially as set forth,

In testimony whereof I afix my signature. 

